My boyfriend and I have been looking at engagement rings, woo! I don't know a whole lot about them, but obviously we're looking for the best quality at an affordable price. Is there a "normal" size for a diamond? I'm just curious about the size most people have. Also, we did a web search on a jewelry store site where you search the four Cs (you choose the setting and diamond separately). We found a diamond that was good in all areas except the clarity was the lowest on the chart. Do you think that matters? Or would it not be noticeable? Thanks!